When changing oils, NEVER ever leave the oil bottle at shop. Because the money that we are paying for oil, also includes the price of bottle as well. So better dump it outside somewhere by yourself and don't leave it at shop. Even for motor cycles oils.
Because oil shop owners sell these bottles to the people who collect the nice conditioned bottles and use them for re-filling purpose.
And when you go for oil change, then before the seal is broken, check the bottle by yourself. It has to be NEW & Shining look and no dirt or stink. If its not, then oil quality will be highly in doubt.
For example, if junk buyer (kabarriya), buys plastic for Rs. 10/Kg. But for neat & clean empty oil bottles, they even pay double money just for one bottle.